The field of the present invention is a chain tensioner for an engine.
A hydraulic chain tensioner, in general, applies pressure to a chain with a plunger which is biased by oil fed thereto under pressure from a lubricating circuit. In most cases, the flow rate of the oil flowing into the chain tensioner is very small. However, it is impossible to form an oil feed passage having a very small diameter because of machining difficulties. Therefore, an orifice and a leak mechanism are provided in the oil feed passage to reduce the working pressure. Such a technique is disclosed in Japanese Utility Model Laid-Open (Kokai) No. S 59-110459.
A member provided with an orifice employed in the prior art must be fabricated separately from the tensioner cylinder of the hydraulic chain tensioner and must be provided with a minute hole, and the leak groove has a complicated construction. Therefore, the member provided with the orifice is costly.